Substituted piperidines



United States Patent 3,468,892 SUBSTITUTED PIPERIDINES Andrew S. Tomcufcilr, Old Tappan, N.J., Paul F. Fabio, Pearl River, N.Y., and Arlene M. Hofiman, Park Ridge, N.J., assignors to American Cyanamid Company, Stamford, Conn., a corporation of Maine No Drawing. Filed Feb. 7, 1966, Ser. No. 525,337 Claims priority, application Great Britain, Mar. 19, 1965, 11,814/ 65 Int. Cl. C07d 29/12 US. Cl. 260293 8 Claims ABSTRACT OF THE DISCLOSURE Substituted amino alkylene substituted piperidines are described which are prepared by several methods, the preferred method being the reaction of a substituted amino alkylenepiperidine with an intermediate which places a group on the nitrogen of the piperidine. The present compounds are useful in inhibiting the growth of protozoa.

This invention relates to new organic compounds. More particularly, it relates to substituted alkylenepiperidines and methods of preparation thereof.

The novel compounds of this invention may be illustrated by the following formula:

wherein R is lower alkyl; R is H or alkyl of from l-l2 carbon atoms, aralkyl or cycloalkyl; R is a carbon atom which is unsaturated by being part of a substituted aryl radical of the benzene type series or part of an aromatic heterocyclic ring of at least ring atoms containing not more than four hetero atoms or by being a carbonyl carbon; n is 3 or 4 and the pharmaceutically acceptable salts of the above described compounds.

When R is an aryl or substituted aryl radical, it may be for example, a chlorophenyl, nitrophenyl, aminophenyl, acetamidophenyl, benzenesulfonamidophenyl, naphthyl, or aminonaphthyl radical.

When R is a substituted carbonyl carbon, besides being bonded to the piperidine nucleus it is also preferably bonded to a phenyl, biphenyl, halophenyl, dichlorophenyl, phenyltriazolyl, phenylazophenyl, benzyloxy, nitrofuryl, alkoxy, or trihalomethyl group.

When R is an aromatic heterocyclic radical, the heterocycle contains not more than four hetero atoms and the remainder are carbon atoms. Among the heterocyclic compounds found useful in preparing the products of the present invention (wherein R is heterocyclic) are, for example,

2-halopyridines, 4-halopyridines, 5-nitro-2-halopyridines, 2,5-dihalopyrimidines, 2-halothiazoles, 5-nitro-2-halothiazoles, 2-halobenzothiazoles, 2-ha1o-6-alkoxybenzothiazoles, Z-halobenzoxazoles, 2-halo-5-nitro-l ,3 ,4-thiadiazoles, 4,7 -dihaloquinolines, 2-haloquinolines,

4-h alo-6-methoxyquinolines, 6-halopurines, Z-halopyrazines,

3,468,892 Patented Sept. 23, 1969 "ice Among the new compounds of this invention are, for example,

1-benzoyl- 3-dimethylaminopropyl piperidine;

1- (4-chlor0phenyl) -4- (3-dimethoxylaminopropyl) piperidine;

4'- [.4- dimethylaminopropyl) -1-piperidinyl] acetanilide;

4-( 3 -dimethylaminopropyl)-1-(4-pyridy1 )piperidine;

1- (7-chloro-4-quinolyl) -4 3-dimethylaminopropyl) piperidine;

2-[4-(3-dimethylaminopropyl)-1-piperidinyl]benzothiazole;

4- 4-dimethylaminobutyl -1- (4-nitrophenyl pip eridine;

1-(4-chlorophenyl)-4-(3-dimethylarninobutyl)- piperidine;

and 4- 3 -dimethylaminopropyl-1- (4-methoxyphenyl) piperidine.

The pharmaceutically acceptable salts of this invention include such salts as hydrochlorides, sulfates, m-aleates, fumarates, and 1,1-methylene-bis-(2 naphthol-3-carboxylates) and quaternary salts.

The free bases of the compounds of the present invention are, in general, oils or lower melting solids, somewhat soluble in water and easily soluble in lower alkanols, benzene, toluene, acetone, chloroform or the like. The salts of the present invention are characteristically soluble in water and other hydroxylated solvents and are usually insoluble in non-polar solvent.

The compounds of the present invention may be conveniently prepared by reacting a compound of the formula:

GHQFN HN Ra wherein R R and n are as defined hereinabove with the compound R Z wherein Z is halogen, OH, O-alkyl, OSO -alkyl, OSO -aryl, or an anhydride residue to form the product of the invention. The above reaction is usually carried out according to procedures well known in the art. For example, when Z is halogen the reaction may be carried out in a solvent such as, for example, a j3-alkoxy alkanol, a lower alkanol, benzene, toluene, tetrahydrofuran, phenol or the like, and the reaction is then usually carried out by heating the reaction mixture in the presence of an acid acceptor such as a bicarbonate, triethylamine, or the like.

The compounds of the present invention may also be prepared by reacting a compound of the formula:

wherein Y is halogen, ()H, OSO -alkyl or OSO -aIyl with an amine of the formula:

in which n, R R and R are as defined hereinbefore. The reaction is usually carried out by heating the hexa-hydropyridine reactant in the presence of an excess of HNR R in a solvent at an elevated temperature.

This invention also includes compositions of matter comprising a pharmaceutically acceptable carrier and a compound of the present invention or pharmaceutically acceptable salts thereof said compositions of matter capable of being administered at a dose of 1 mg. to 500 mg. of compound or salt thereof per kilogram of body weight of the warm blooded animal being treated.

The compounds of the present invention are active in inhibiting the growth of protozoa. They are particularly active in inhibiting protozoa of the genus Trypanosoma, different species of which are known to be the causative agent of serious parasitic diseases in man and animals (e.g., Trypanosomiasis or sleeping sickness). For example, the compound 4'-[4-(3-dirnethylaminopropyl)-1- piperidinyl1-acetanilide has been found to be highly active against experimental infections with T rypan'osoma cruzi in mice. T rypanosoma cruzi is the causative agent of Chagas disease in South America, an American Trypanosomiasis.

The substituted piperidines described above may be dispensed as the active ingredient in compositions of the compound and an edible carrier. While the amount of drug to be given daily will depend on many factors such as size, Weight, age, etc. of the warm blooded animal, it has been found that a daily intake of from 1 mg. to 500 mg./kg. of body weight will produce good results in warm blooded animals. The dosage unit may be in a form for a single unit per day, or smaller forms for use as multiple units per day. In the case of tablets, they may be of larger size, scored for use as fractional units one or more times per day.

The compositions can be dispensed in the form of soft or hard-shell gelatin capsules. Also present in the capsules may be diluents such as lactose, starch, magnesium oxide, magnesium stearate and the like. The capsules may be large enough to provide the desirable daily dosage or smaller to be used in multiple doses per day.

The compositions may be dispensed as parenteral solutions or suspensions. If larger doses in small amounts are desirable it may in some cases be necessary to use parenteral suspensions.

The compositions of the present invention may take the form of syrups or pediatric drops, Such formulations usually contain one or more of the following; suspensing agents, buffer salts, stabilizers, preservatives, etc.

The testing of the present compounds against T. cruzi is carried out as follows: seven to eight week old Manor strain albino mice are inoculated subcutaneously with approximately 50,000 parasites (from infected donor mice), the median survival time of untreated mice being thirteen to sixteen days. Candidate compositions are administered by drug-diet on days 612 postinoculation. The principal criterion of chemotherapeutic activity is the survival time of treated mice relative to untreated mice but examination of the peripheral blood and of various internal organs for parasites is also done in some experiments. Activity is unaffected when the compounds are administered by gavage, or by subcutaneous or intraperitoneal injection. When compounds of the invention are administered to mice infected with T. cruzi as above, over 80% of the animals are healthy and free of parasites thirty days after the date of infection.

The following examples described in detail the preparation of representative piperazines of the present invention.

EXAMPLE 1 Preparation of 4-(3-dimethylaminopropyl)-1-(4-nitrophenyl) piperidine A mixture of 30.9 grams of 4-(3-dimethylaminopropyl) piperidine, 26.2 grams of 1-fluoro-4-nitrobenzene, 20.1 grams of sodium bicarbonate, and 500 ml. of toluene is stirred at reflux for twenty-four hours. After cooling to room temperature, the inorganic solids are filtered off and the filtrate concentrated under reduced pressure to yield a yellow solid. Recrystallization from boiling ethyl acetate gives the pure compound melting at 93 -95 C.

Treatment of the free base with an acetone solution of maleic acid gives the monomaleate salt melting at 132- 134 C.

The 1-fluoro-4nitrobenzene starting material may be replaced by the corresponding l-chloro, 'l-bromo, or 1- iodo-4-nitrobenzene to produce the desired compound.

EXAMPLE 2 Preparation of 4-(3-dimethylaminopropyl)-1-(4-aminophenyl) piperidine trihydrochloride EXAMPLE 3 Preparation of 4 3-dimethyl amino propyl) l (4- acetamidophenyl)piperidine A solution of 12.0 grams of 4-(3-dimethylaminopropyl)- 1-(4-aminophenyl)piperidine in 200 ml. of ethyl acetate (prepared as in Example 2) is treated with 15 ml. of acetic anhydride at room temperature for two hours. The reaction mixture is concentrated to dryness under reduced pressure. Recrystallization of the residue from ether gives the pure compound melting at 107 -109 C. Treatment of the compound with an acetone solution of maleic acid gives the maleate salt melting at 148 C. with decomposition.

EXAMPLE 4 Preparation of 4-(3-dimethylaminopropyl)-1-(4-lauramidophenyl) piperidine hydrochloride A solution of 4.5 grams of 4-(3-dimethylaminopropyl)- 1-(4-aminophenyl)piperidine in 100 ml. of ethyl acetate (prepared as in Example 2) is treated with 5.7 grams of lauroyl chloride. After several hours, the precipitate is collected and recrystallized from ethanol to give the pure compound melting at 190 C. with decomposition.

EXAMPLE 5 Preparation of 4-(3-dimethylaminopropyl)-1-(4- carbethoxyaminophenyl)piperidine dihydrochloride The subject compound is prepared by the procedure of Example 4, ethyl chloroformate replacing the lauroyl chloride. The pure compound melts at 225 C. with decomposition.

EXAMPLE 6 Preparation of 4- 3-dimethylaminopropyl 1 -(4- benzamidophenyl) piperidine hydrochloride The title compound is prepared by the procedure of Example 4, benzoyl chloride replacing the lauroyl chloride. The compound melts at 214-217 C. with decomposition.

EXAMPLE 7 Preparation of 4-(3-dimethylaminopropyl)-1-(4-benzenesulfonamidophenyl)piperidine hydrochloride The subject compound is prepared by the procedure of Example 4, benzenesulfonyl chloride replacing the lauroyl chloride. The compound melts at 192 C.

EXAMPLE 8 Preparation of 4-(B-dimethylaminopropyl)-1-(4- phenylureidophenyl)piperidine maleate A solution of 3.5 grams of 4-(3-dimethylaminopropyl)- l-(4-aminophenyl)piperidine in 100 ml. of ethyl acetate (prepared as in Example 2) is treated with 2.4 grams of phenyl isocyanate dissolved in 100 ml. of ethyl acetate. After standing at room temperature, the precipitate is collected and treated with an acetone solution of maleic acid to give the title compound melting at 140-142 C.

EXAMPLE 9 Preparation of 4- 3- (N-methylbutylamino)propyl] -1- nitrophenyl) piperidine hydrochloride The compound is prepared essentially by the procedure of Example 1, 4-[3-(N-methylbutylamino)propyl]piperidine replacing the 4-(3-dimethylaminopropyl)piperidine. The compound melts at 149152 C.

EXAMPLE Preparation of 4-[3-(N-methylbutylamino)propyl]-1- (4-acetamidophenyl)piperdine maleate The catalytic reduction of 4-[3-(N-methylbutylamino) propyl]-1-( t-nitrophenyl)piperidine (Example 9) by the procedure of Example 2 gives an ethyl acetate solution of 4 [3 (N methylbutylamino)propyl] 1 (4- aminophenyl)piperidine. This is acetylated and converted to its maleic acid salt by the procedure of Example 3 to yield the subject compound melting at 98-102 C. with decomposition.

EXAMPLE 11 Preparation of 4- 3-(N-methyl-n-octylamino)propyl] -1- (4nitrophenyl)piperidine maleate The above compound is prepared by the method of Example 1, 4-[3-(N-methyl-n-octylamino)propyl]piperidine replacing the 4-(3-dimethy1aminopropyl)piperidine. It melts at 7577 C. with decomposition.

EXAMPLE 12 Preparation of 4-(3-dimethylaminopropyl)-1-(4- biphenyloyl)piperidine hydrochloride A solution of 5.5 grams of 4-biphenyloyl chloride in 200 ml. of diethyl ether is treated with a solution of 4.3 grams of 4-(S-dimethylaminopropyl)piperidine in 100 ml. of diethyl ether, giving the title compound, melting point 17017l C.

EXAMPLE 13 Preparation of 4-(3-dimethylaminopropyl)-1-(4- iodobenzoyl)piperidine hydrochloride The above compound is prepared by the method of Example 12, 4-iodobenzoyl chloride replacing the 4-biphenyloyl chloride. After recrystallization from isopropanel, the compound melts at 17017l C.

EXAMPLE 14 Preparation of 4-(3-dimethylaminopropyl)-1-(2- phenyl-ZH-l,2,3-triazol-4-oyl)piperidine EMMPLE 15 Preparation of 4-(3-dimethylarninopropyl)-l-(4- phenylazobenzoyl)piperidine hydrochloride The above compound is prepared by the method of Example 12, 4-phenylazobenzoyl chloride replacing the 4'biphenyloyl chloride. The compound melts at 180 181 C.

6 EXAMPLE 16 Preparation of 4-[3-(N-methylbutylamino)propyl]1- (2-phenyl-2H-1,2,3-triazol-4-oyl)piperidine dimaleate The above compound is prepared by the procedure of Example 14, 4-[3-(N methylbutylarnino)propyl]piperidine replacing the 4-(3-dimethylaminopropyl)piperidine. It melts at 167 C. with decomposition.

EXAMPLE 17 Preparation of 7-chloro-4- [4- 3-dimethylaminopropyl l-piperidino] quinoline The preparation of the above compound is accomplished essentially by the procedure described in Example 1, an equivalent quantity of 4,7-dichloroquinoline replacing the 1-fiuoro-4-nitro'benzene. The compound melts at 6972 C., while the trifumarate salt melts at 159- 161 C.

EXAMPLE 18 Preparation of 4-[4-(3-dimethylaminopropyl)-lpiperidino] pyridine dimaleate The preparation of the above compound is accomplished by the procedure substantially as described in Example 1, an equivalent quantity of 4-chloropyridine replacing the 1-fluoro-4-nitrobenzene. The pure compound melts at 111l14 C. with decomposition.

EXAMPLE 19 Preparation of 2-[4-(3-dimethylaminopropyl)-1- piperidinoJbenzothiazole maleate The preparation of the above compound is accomplished by following the procedure of Example 1, an equivalent quantity of 2-chlorobenzothiazole replacing the 1-fluoro-4-nitrobenzene. The pure compound melts at 172 C. with decomposition.

EXAMPLE 20 Preparation of 2- [4- (3-dimethylaminopropyl )-1' piperidino]-5-nitropyridine dimaleate The preparation of the above compound is accomplished by following the procedure of Example 1, an equivalent amount of 2-chloro-5-nitropyridine replacing the 1-fiuoro-4-nitrobenzene. The pure compound melts at 150151 C.

EXAMPLE 21 Preparation of 1- [4- 3-dirnethylaminopropyl-1- piperidino] -4-methylthioxanthone Synthesis of the above compound is accomplished by the procedure described in Example 1, an equivalent of 1-chloro-4-methylthioxanthone replacing the 1-fiuoro-4- nitrobenzene. The pure compound melts at 7880 C.

EXAMPLE 22 Preparation of 3-(3-dimethylaminopropyl)-1-(4- biphenyloyl)piperidine hydrochloride The compound is prepared by the method of Example 12, 3-(3 dimethylaminopropyl)piperidine replacing the 4-(3 dimethylaminopropyl)piperdine. It is purified by recrystallization from a mixture of isopropanol and diethyl ether and melts at 150-152 C.

EXAMPLE 23 Preparation of 3-(3-dimethylaminopropyl)-1-(4- nitrophenyl piperidine maleate The compound is prepared by the procedure of Example 1, 3-(3-dimethylaminopropyl)piperidine replacing the 4-(3-dimethylaminopropyl)piperidine. It melts at 126-127 C.

EXAMPLE 26 Preparation of 2- (3-dimethylaminopropyl)-l- (4-biphenyloyl)pipen'dine hydrochloride The compound is prepared by the method of Example 12, 2-(3 dhnethylaminopropyl)piperidine replacing the 4-(3-dimethylaminopropyl)piperidine. The compound melts at 175-l78 C. with decomposition.

EXAMPLE 27 Preparation of 2 (3-dimethylaminopropyl) -l- (4-nitrophenyl)piperidine maleate The compound is prepared by the procedure of Example 1, 2-(3-dimethylaminopropyl)piperidine replacing the 4-(3-dimethylaminopropyl)piperidine. The compound melts at 123 -l25 C.

EXAMPLE 28 Preparation of 4-(4-dimethylaminobutyl) -1- (4-nitrophenyl)piperidine hydrochloride The title compound is prepared by the method of Example 1, 4-(4-dimethylaminobntyl)piperidine replacrng the 4-(3-dimethylaminopropyl)piperidine. The compound melts at 160-163 C.

EXAMPLE 29 Preparation of 4-(4-dimethylaminobutyl) -1- (4-biphenyloyl piperidine hydrochloride The compound is prepared by the method of Example 12, 4-(4-dimethylaminobutyl)piperidine replacmg the 4-(3-dimethylaminopropyl)piperidine. It melts at 163 165 C.

EXAMPLE 30 Preparation of 4-(4-dimethylaminobutyl)-1-(2-p hcnyl- 2H-1,2,3-triazol-4-oyl)piperidine hydrochloride The subject compound is prepared by the procedure of Example 14, 4-(4-dimethylaminobutyl)piperldine replacing the 4-(3-dimethylaminopropyl)piperidme. It melts at 145 147 C.

EXAMPLE 31 Preparation of 4-(4-dimethylaminobutyl)-1- (7-chloro-4-quinolyl)piperidine difumarate The subject compound is prepared by the method of Example 17, the 4-(4-dimethylaminobutyl)piperidine replacing the 4-(3-dimethylaminopropyl)piperidine. It melts at 178l80 C.

EXAMPLE 32 Preparation of 1'(4-amino-1-naphthyl)-4-(3-dimethy1- aminopropyl)piperidine trihydrochloride Preparation of the above compound is carried out by the procedure of Example 2, 4-(3-dimethylaminopropyl)- 1-(4-nitr0naphthyl)piperidine replacing the 4-(3-dime thylamino pro pyl) l- (4'-nitrophenyl) piperidine.

8 EXAMPLE 33 Preparation of 1-(4-acetamido-l-naphthyl)-4- (3-dimethylaminopropyl)piperidine Utilizing the procedure described in Example 3, a solution of 1- (4-aminonaphthyl) -4- 3-dimethylaminopropyl)piperidine in ethylacetate, as described in Example 32, is treated with acetic anhydride to yield the compound of the example.

EXAMPLE 34 Preparation of 4- [3- (N-methylcyclohexylamino) propyl] l- (4-biphenyloyl piperidine hydrochloride The subject compound is prepared by the procedure of Example 12, 4-[3-(N-methylcyclohexylamino)propyH- piperidine replacing the 4-(3-dimethylaminopropyl)- piperidine. The compound melts at 232-234 C.

EXAMPLE 35 Preparation of 4- [3 (N-methyl-phenylethylamino propyl] -1- (4-biphenyloyl) piperidine hydrochloride The subject compound is prepared by the procedure of Example 12, 4-[3-(N-methylphenylethylamino)propy1]piperidine replacing the 4-(3-dimethylaminopropyl)- piperidine. The compound melts at 195 -197 C.

EXAMPLE 36 Preparation of 4- 3-climethylaminopropyl) -1- (4-nitro-1-naphthyl)piperidine maleate The subject compound is prepared by the procedure of Example 1, 1-iodo-4-nitronaphthalene replacing the 1-fluoro-4-nitrobenzene.

EXAMPLE 37 Preparation of 4-(3-dimethylaminopropyl)-1- l-phenyl-S-tetrazolyl pipen'dine maleate The subject compound is prepared by the method of Example 1, S-bromo-l-phenyltetrazole replacing the 1-fiuoro-4-nitrobenzene. The compound melts at 157" C.

EXAMPLE 38 Preparation of 4- (3-dimethylaminopropyl) -1- (S-nitro-Z-thiazolyl piperidine maleate The subject compound is prepared by the procedure of Example 1, 5-nitro-2-bromothiazole replacing the 1-fiuoro-4-nitrobenzene. The compound melts below 60C.

EXAMPLE 39 Preparation of 4-(3-dimethylaminopropyl)-1-(3-chloro- Z-quinoxalinyl piperidine hydrochloride The subject compound is prepared by the method of Example 1, 2,3-dichloroquinoaxaline replacing the 1-fiuoro-4-nitrobenzene. The compound melts at 212- 214 C What is claimedis: 1. A piperidine of the formula:

R1 2)n N R N R2 wherein R is lower alkyl, R is selected from the group consisting of hydrogen, lower alkyl and phenylloweralkyl, R is selected from the group consisting of aminophenyl, nitrophenyl, alkanoylaminophenyl of 1 to 11 carbon atoms, carboloweralkoxyaminophenyl, benzamidophenyl, benzenesulfonamidophenyl, phenylu-reidophenyl, biphenyloyl and iodobenzoyl, n is an integer of 3 to 4 and the pharmaceutically acceptable salts thereof.

2. The piperidine according to claim '1, 4-'(3-dimethylaminopropyl) 1 (4 benzenesu1fonamidophenyl)- piperidine.

3. The piperidine according to claim 1, 3-(3-climethy1- aminopropyl)-1-(4-biphenyloyl)-pipe1'idine.

4. The piperidine according to claim 1, 4-[3-(-N- methylbutylamin0)propyl] l (4 acetamidophenyD- piperidine.

5. The piperidine according to claim 1, 4-(3-dimethylaminopl'opyl)-1-(4amin0phenyl)-piperidine.

6. The piperidine according to claim 1, 4(3-dimethylaminopropyl) -1-(4-benzamid0phenyl) -pip eridinc 7. The piperidine according to claim 1, 4-[3 (N- methylbutylamino)propyl] 1 (4 nitrophenyD-piperidine.

8. The piperidine according to claim 1, S-(B-dimethylaminopropyl)-1-(4-nitr0phenyD-piperidine,

10 References Cited UNITED STATES PATENTS HENRY R. JILES, Primary Examiner G. THOMAS TODD, Assistant Examiner US. 01. X.R. 260-156, 287, 288, 293,47, 294, 294.3, 294,7 

